A clamping system of this type is known from U.S. Pat. No. 3,964,773. The cross-section of the band of the collar is, for example, substantially V-shaped or U-shaped, so that each of the flanges formed by the cross-sectional shape bears against the bearing surface of the end of a respective one of the tubes. Thus, tightening the collar tends to hold the tubes one against the other. A V-shaped cross-section is advantageous insofar as, when the collar is tightened, it urges the tubes together.
For example, the means for tightening the band comprise a nut-and-bolt system. Thus, the ends of the band can be turned out so as to form bearing tabs provided with holes through which a bolt can be inserted. A nut is disposed behind one of the tabs so that turning the screw causes the collar to be tightened.
U.S. Pat. No. 3,964,773 recommends using a sealing washer between the ends of the two tubes. The washer is a conical washer which is engaged in the flared end of one of the tubes and against which the end of the other tube bears, said end of the other tube having a shape substantially complementary to the shape of said flared end.
The washer of the clamping system of U.S. Pat. No. 3,964,773 which, in the example presented by that document, serves to provide sealing, constitutes a part that is entirely distinct from the clamping collar, which must be handled separately therefrom. As a result, the entire clamping system is relatively complicated to fit, since the operator has to handle a plurality of parts and has to position each one of them correctly relative to the tubes.
Thus, in U.S. Pat. No. 3,964,733, firstly the washer must be disposed correctly relative to the end of the first tube, the end of the second tube must be disposed correctly relative to the washer, and the assembly made up of the two tubes and of the washer must be held together, and then the collar must be put in place on the assembly and must be tightened.